Nervous System Overview and Functions
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Nervous System Overview and Functions

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Questions and Answers

What is the primary function of the axon in a neuron?

  • To support the neuron's structure
  • To store neurotransmitters
  • To conduct nerve signals away from the soma (correct)
  • To process synaptic signals

    • What are axon collaterals?

  • Branches of the axon (correct)
  • Branches that enhance signal speed
  • The part of the neuron responsible for synapse formation
  • Segments between the nodes of Ranvier

    • What is the axon hillock?

  • The initial segment of the myelin sheath
  • The terminal point of the neuron
  • The site where action potentials are generated (correct)
  • The junction between dendrites and soma

    • What is the role of the myelin sheath?

    <p>To facilitate rapid conduction of signals along the axon</p> Signup and view all the answers

    Which part of the neuron contains the nucleus?

    <p>Soma</p> Signup and view all the answers

    What is the primary type of cell from which brain tumors can often arise?

    <p>Astrocytes</p> Signup and view all the answers

    Which component primarily forms the myelin sheath in the central nervous system (CNS)?

    <p>Oligodendrocytes</p> Signup and view all the answers

    What challenge does the blood-brain barrier pose for treating gliomas?

    <p>Decreases effectiveness of chemotherapy</p> Signup and view all the answers

    What is a characteristic feature of mature neurons regarding cell division?

    <p>They seldom form tumors.</p> Signup and view all the answers

    What is the composition of the myelin sheath?

    <p>20% protein and 80% lipid</p> Signup and view all the answers

    What function do sensory neurons perform in the nervous system?

    <p>Sense and transmit signals to the CNS</p> Signup and view all the answers

    Which neuron type is confined solely to the central nervous system?

    <p>Interneurons</p> Signup and view all the answers

    What is the role of the soma in a neuron?

    <p>Control cellular activities and contain the nucleus</p> Signup and view all the answers

    What is the primary function of dendrites in a neuron?

    <p>Receive signals from other neurons</p> Signup and view all the answers

    Which component is responsible for the initial segment of a neuron's axon?

    <p>Axon hillock</p> Signup and view all the answers

    What is contained within the cytoplasm of the soma?

    <p>Mitochondria and lysosomes</p> Signup and view all the answers

    How do dendrites enhance a neuron's ability to process information?

    <p>By branching out to receive more signals</p> Signup and view all the answers

    What is the function of the myelin sheath?

    <p>To facilitate signal conduction along the axon</p> Signup and view all the answers

    Which part of the neuron is responsible for integrating incoming signals?

    <p>Soma</p> Signup and view all the answers

    Which structure is responsible for the direction of signal transmission in a neuron?

    <p>Axon</p> Signup and view all the answers

    What is the role of the axon in a neuron?

    <p>To transmit signals away from the soma</p> Signup and view all the answers

    What component of a neuron is responsible for its structural integrity?

    <p>Cytoskeleton</p> Signup and view all the answers

    What can be inferred about the relationship between the number of dendrites and a neuron's information processing capacity?

    <p>More dendrites enhance processing capacity</p> Signup and view all the answers

    What structural feature of dendrites resembles tree branches in winter?

    <p>Dendritic branches</p> Signup and view all the answers

    Which part of a neuron is involved in the initial reception of signals?

    <p>Dendrites</p> Signup and view all the answers

    What is the significance of the myelin sheath in neural transmission?

    <p>To speed up signal transmission</p> Signup and view all the answers

    What is the primary function of sensory (afferent) neurons?

    <p>Detect stimuli and transmit information to the CNS</p> Signup and view all the answers

    Which of the following divisions is part of the peripheral nervous system?

    <p>Nerves</p> Signup and view all the answers

    What type of neuron is involved in the integrative function within the CNS?

    <p>Interneurons</p> Signup and view all the answers

    Which property of neurons allows them to respond to environmental changes?

    <p>Excitability</p> Signup and view all the answers

    What is the role of motor (efferent) neurons?

    <p>Transmit signals away from the CNS to effectors</p> Signup and view all the answers

    Which subdivision of the nervous system is responsible for the sympathetic division?

    <p>Autonomic nervous system</p> Signup and view all the answers

    What is commonly secreted at the end of a nerve fiber when an electrical signal reaches it?

    <p>Neurotransmitters</p> Signup and view all the answers

    Which type of division in the nervous system is responsible for voluntary motor control?

    <p>Somatic motor division</p> Signup and view all the answers

    What is the primary function of the synaptic knob?

    <p>To form a junction with the next cell</p> Signup and view all the answers

    What is the main distinguishing feature of an axon compared to other neuron structures?

    <p>It has only one axon per neuron</p> Signup and view all the answers

    What do Schwann cells contribute to the axon?

    <p>They form the myelin sheath</p> Signup and view all the answers

    Which part of the axon is responsible for initiating the action potential?

    <p>Axon hillock</p> Signup and view all the answers

    Which structure is NOT part of the axon?

    <p>Dendrite</p> Signup and view all the answers

    What are the gaps between myelin sheaths called?

    <p>Nodes of Ranvier</p> Signup and view all the answers

    What is axoplasm?

    <p>The fluid inside the axon</p> Signup and view all the answers

    Which component of the neuron is directly involved in the transmission of electrical signals?

    <p>Axon</p> Signup and view all the answers

    Study Notes

    Nervous Tissue Overview

    • The nervous system is complex and fundamental to conscious experience, personality, and behavior
    • It coordinates with the endocrine system
    • Endocrine system communicates via chemical messengers (hormones) released into the bloodstream
    • Nervous system uses electrical and chemical signals to transmit messages between cells

    Nervous System Tasks

    • Sense organs gather and transmit information to the spinal cord and brain
    • The brain and spinal cord process this information, recalling past experiences to determine the appropriate response
    • The brain and spinal cord command muscles and glands to execute the response

    Nervous System Subdivisions

    • Central Nervous System (CNS):
      • Brain and spinal cord
      • Enclosed in bony coverings (cranium and vertebral column)
    • Peripheral Nervous System (PNS):
      • All nervous system components outside the brain and spinal cord
      • Contains:
        • Nerves: Bundles of nerve fibers (axons) with connective tissue
        • Ganglia: Knot-like swellings in nerves containing neuron cell bodies

    Peripheral Nervous System Subdivisions (Functional)

    • Sensory (Afferent) Division:
      • Carries sensory signals from various receptors to the CNS
      • Includes:
        • Somatic Sensory Division: Skin, muscles, bones, and joints
        • Visceral Sensory Division: Internal organs (heart, lungs, stomach, bladder)
    • Motor (Efferent) Division: Carries signals from CNS to effectors that carry out the response
      • Includes:
        • Somatic Motor Division: Skeletal muscles (voluntary movements and reflexes)
        • Visceral Motor Division (Autonomic Nervous System):
          • Sympathetic Division: Prepares the body for action (accelerates heart rate, respiration)
          • Parasympathetic Division: Calming effect (slows heart rate, stimulates digestion and urination)

    Universal Neuron Properties

    • Excitability (Irritability) : Responds to stimuli
    • Conductivity: Carries electrical signals
    • Secretion: Releases chemical neurotransmitters to stimulate next cells

    Neuron Functional Classes

    • Sensory (Afferent) neurons: Detect stimuli and transmit signals to the CNS
    • Interneurons (Association neurons): Located entirely within the CNS, process, store, and retrieve information, and make decisions about how the body should respond to stimuli
    • Motor (Efferent) neurons: Transmit signals from the CNS to muscles and glands (effectors)

    Neuron Structure

    • Soma (Neurosoma, Cell Body): Control center, contains nucleus and other organelles
    • Dendrites: Receive signals from other neurons
    • Axon (Nerve Fiber): Carries signals away from the soma
    • Axon Collaterals: Branches of axons
    • Synaptic Knobs (Terminal Buttons): Form synapses with the next cell and release neurotransmitters
    • Myelin Sheath: Insulating layer around some axons for faster signal transmission
      • Formed by oligodendrocytes in CNS and Schwann cells in PNS
      • Consists of 20% protein and 80% lipid
      • Nodes of Ranvier and internodes are segmented sections

    Neuron Classification

    • Multipolar: Most common; many dendrites, one axon (brain and spinal cord)
    • Bipolar: One axon, one dendrite (olfactory cells, retina, inner ear)
    • Unipolar: One process leading away from the soma (sensory neurons); from skin/organs to spinal cord
    • Anaxonic: Many dendrites, no axon (in the brain)

    Support Cells (Neuroglia)

    • Outnumber neurons in the nervous system.
    • Provide structural support and protection
    • Types include:
      • Oligodendrocytes: Form myelin sheaths in CNS
      • Ependymal Cells: Line brain cavities, secrete and circulate cerebrospinal fluid (CSF)
      • Microglia: Small macrophages that remove cellular debris
      • Astrocytes: Most abundant, form framework, stimulate blood-brain barrier formation, convert glucose to lactate, and provide nourishment to neurons
      • Schwann Cells: Form myelin sheaths in PNS; assist in fiber regeneration
      • Satellite Cells: Surround somas in ganglia, regulate chemical environment

    Myelin

    • Insulating layer around some axons
    • Speeds signal transmission

    Diseases of the Myelin Sheath

    • Multiple Sclerosis: Degradation of myelin in the CNS

    Glial Cells and Brain Tumors

    • Tumors: Masses of rapidly dividing cells
    • Brain Tumors: Arise from meninges, metastasis from other organs, or glial cells
    • Gliomas: Rapidly growing, highly malignant brain tumors

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    Nervous Tissue Lecture Notes PDF

    Description

    Explore the complexities of the nervous system, including its coordination with the endocrine system and the roles of the central and peripheral nervous systems. This quiz covers how the brain and spinal cord process information and command responses. Test your understanding of the fundamental tasks and subdivisions of the nervous system.

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